Deicing system for aircraft surfaces



April 11, 1950 E. P. PALMATIER DEICING SYSTEM FOR AIRCRAFT SURFACE Filed Jan. 11, 1944 5 Sheets-Sheet l 1950 E. P. PALMATIER mmcmc SYSTEM FOR AIRCRAFT SURFACES '5 Sheets-Shet 2 Filed Jan. 11, 1944 I N VEN TOR E. P. PALMATIER DEICING SYSTEM FOR AIR April 11, 1950 CRAFT SURFACES 5 Sheets-Sheet 3 Filed Jan. 11, 1944 'INVENTOR [we refiffiz/mafier "Ill/Ill Patented Apr. 11,1950

DE'ICING SYSTEMFOR AIRCRAFT SURFACES Everett P. P almatier, Upper Montclair, N. J as- Signor to Curtiss-Wright Corporation, a corpu ration of Delaware "Application January 11, 1944, Serial nolsimsii My invention relates to a system for ole-icing rotatable aircraft surfaces.

In accordance with my invention, the space enclosed by the aircraft spinner serves as a chamber from which a hot gaseous medium is passed to the propeller blades and the blade cuffs.

It is a feature of my invention that the propeller blade and/or blade cuffs are subjected,'in a novel manner, to the action of a hot gaseous medium for de-icing purposes. It is a, further feature of my invention that the respective streams-of hot gases passing through a hollow propeller blade and blade cuff are de flected toward the leading edgesof said blade and cufi. I

Various other objects and advantages of my invention will become apparent from the following detailed description.

' My invention resides in the art, system and arrangements for deeicing rotatable aircraft surfaces as hereinafter described and claimed.

For an understanding of my invention and for an illustration of one of the many forms thereof, reference is to be had to the accompanying drawings, in which:

Figure 1 is a vertical sectional view, partly in elevation, showing a de-icing arrangement as constructed in accordance with my invention;

' Fig. 2 is a transverse, vertical sectional view, partly in elevation, taken on the line 2-2 of 1 looking in the direction of the arrows;

' Figs. 2a, 2b, 2c are transverse sectional views taken on the respective lines 2a,'2a, 2b- 2b and 2c-'-2'c of Fig. 2; I Fig. 3 is 'a' fragmentary sectional view' showing the 'end of a propeller blade; Fig. 4 is a transverse'horizontal sectional view taken onth'e line l '--'l of Fig. llooking" in the dir'ectio'n'of the arrows; 1 "1 Fig. 5 i a sectional view, partly in elevation. showing a modified feature'of the invention;

Fig. 6 is a schematic view showing an air heatin system forthe spinner, propeller'blade and blade cuff arrangement of the invention;

Fig. 7 is a vertical sectional view, partly in elevation, showing an additional feature of the invention; I I. I

Fig. 8-is a transverse sectional view, partlyin elevation, taken on the line 8--8'of Fig. 7 looking in the direction of the arrows; and

Fig. 9 isa sectional'view taken on the line 9-5 of Fig 8 looking in the direction "of the arrows. Referring to Fig. 1, I have shown the i of an aircraft engine having the propeller shaft 4 Claims. (Cl. '244134-) 2 I 2 extending therefrom. f Secured'in known-manner to the shaft 2 is the propeller hub 3 which comprise a plurality" of radially extending sockets t for therespe'ctive' Ipropeller blades 5. If desired, but by no means necessarily, a heat-protective box or" housing 3a may be disposed around the hub 3, this housing 3abeing provided with passages through which the respective propeller blades 5 extend. As hereinshown, the hub 3 has secured to the'forwar'd end thereof a housing 6 within which is disposed the motor and other mechanism utilizable for changing the pitch ofthepropellr blades 5 as known in the art. i

Bolted-or otherwise suitably secured to a rear section of'the hub 3 is a disk '1- terminating in a circular flange Ta concentrically disposed with respect to the propeller shaft 2. Spaced from the flange Ta to thereby form a circular slot 8 is a circular flange 9a of a curved member 9', the flanges 9a being concentrically-disposed with respect to the flange 1a and said member 9 being secured insuitable manner to the rear section of the spinner H! which is"attached in known manner to the hub 3 so as to be rotatable therewith as a unit. As hereinafter described, the flanges Ia and 9a should be secured to each other in suitable mannenas by spaced connect ing webs.

Disposed'in the aforesaid slot'8' is the circular passage-forming extension [2a of a circular housing l2 secure'd'infix'ed position in any suitable manner, as by a disk l3 attached thereto and tothe engine-nose l. The flanges la, 96: are disposed closely-adjacent the respective walls of the extension 'l2a"and,-pr'eferab1v, packings or other suitable sealing means, not shown. are disposed between adjacentsurfaces defined by said flanges and walls. "Communicating with the housing I 2 is or are one or more pipes Ml through which a heated gaseous medium is supplied in suitable manner to said housing H as hereinafter described.

As herein shown. each of the propeller blades 5 has associated therewith a cull. H5 which is formed froma m'etallic's'hell' l6 shaped into cufi formation. At the trailing edge of the cuff. thev two edges of the shell" l 6" are attached together by a coupling member IT, said shell edges and the member I 1 being secured together by rivets ill. The coupling-member Il terminates short of the outer end of 'the cuff 'and',-'in this area. the trailing shell edgesfiare secured together by a pin. 19 which extendsthrough cylindrical members 20 alternately-'forinednon said, cufi' edges, respectively. The outer end of each cuff I5 has associated therewith a sealing member 2I formed preferably of rubber, this sealing member 2i engaging the adjacent propeller blade surface and anchoring the upper end of the cuff I5 in operative position.

Each cuff I5 further comprises a member 22 disposed interiorly of the shell I6 at the leading cufi' edge and spaced therefrom in generally parallel relation, the shell I6 being secured to the member 22 by rivets 23, or equivalent.

As regards each cuff I5, the. member 22 thereof is seated on a plate 22a which may be formed integrally with the aforesaid coupling member I1; The plate 22a is formed withian opening" which is defined by a circular section 22b having U -configuration. The associated propeller blade 5 extends through this opening andthe U-section 22b cooperates with aflange 5a formed exteriorly on said propeller blade-5 to thereby support the associated cuff I5 in operativeposition; Asshown particularly in Fig. 4,. the-plate 22a'comprises an opening 220 utilizabletas-herehiafter; described.

Formed as an integral part ofthe structure consisting of a the cup1-ing;,member I1 and the plate 22a isa plate-22d upon which the afore said shell I6 is seated, This plate'fld'comprises a tubular section 22e-whichextends inwardly in spaced relation with .respectto'theexterior sur-'- face of the associated propeller blade 5, each tubular section 22a extending; through an opening Iila formed in the-spinner I0;

concentrically disposedwith respect to the tubular section 22s of each plate 22d and secured in suitable mannerto theadjacent surface of the spinner I0 is a tubular member 24'-whlch, in suitable manner; carries acircularpacking or sealing member 25 related, irr' sealing relation, with the adjacent surfaceof said-tubularsection 22c of the plate 22d;

I have hereinbefore=statedthat'the coupling member I7, the plates-22a and 22d together with the tubular section 22e-arean :integral structure. This, in effect, is 'anaccurate statement. However, in actual practiceand as indicatedin Fig. 4, it'will be understood that-the aforesaid structure will consist of separate parts which are assembled in operative relation'and'then suitably-secured together.

In view of the rforegoing- .description, it-will'be understood that each-cuff- Iiincludi-ng the plate 22d and tubular section-22a: thereofa-re secured to each propeller blade="-for movement'therewith as a unit. Accordingly, during a pitch-changing operation, the aforesaid tubu-lar' section. 22a of each plate 22d: moves'rotatably with respect to its'gasket and the-associatedtubular member 24, said gasket 25 --maintainingf'a sealedjoint at all times between rtheserelatively movable parts.

In accordance-with the invention, the propeller blades 5 are ofthehollow -passageflorming' type and the shank'of each blade 5 comprises one or more passages 5b extending transversely-therethrough. Further; as indicated'in Fig. 3, each of the blades 5', at or adjacent its outer end', comprises a-vent"or"passage 5c open-to the-atmosphere.

As indicated-ink Fig: 1; each" of the propeller blades 5 may have'a diifuser 26 secured interiorly thereof in suitable manner, as bygthe interlocking circular tonguesfil'formed: thereon and on the interior blade surface,- respectively. As shown, the deflector 2& comprises channels 26a which are alinedwith'therespective-passages 51) formed in the propeller: blade-shank. These 4 channels 26a form diverging paths which merge into the main diffuser channel 25b which also forms a path diverging in a direction leading toward the tip of the blade.

During flight of the aircraft and when it becomes necessary to subject the propeller blades 5 and the cuffs I5 to a de-icing operation, streams of heated air'or other hot gases pass, by way of the respective pipes I4, into the fixed housing l2. From said housing I2, the hot gases pass, by way of the housing extension 1211, into the chamber defined by the rotating spinner I0.

From this chamber, one stream of the hot gases passes" through the passages 5b of each blade 5, through each difiuser 26 and then through each blade 5, the stream of hot gases emerging from each blade 5 by way of the vent 5c formed at the end thereof. As will be understood, the'hot gases are drawn into and through the propeller blades 5-by centrifugal action in response to rotation thereof. and such centrifugal action of the propeller= blades 5 is appliedto the hot gases in the spinner I0, the housing extension I2a, the housing l2. and.the pipes- 14 although, as-hereinafter described, there should be a source of .positive pressure which causes the hot gases to move through the pipes-I4 toward the housing I2; The diffuser ZGis advantageous be cause the channels zfid and 26b thereof, as stated,

form diverging paths which decrease the velocity of the hot'gases. Fora given volume of hot gases passing into the blade per unit oftime, the blade passages'Bb may have smaller c-rosssectional area if said diffuser 26.is employed as-described.

From said chamber defined by the spinner I0, another stream of hot gases passes outwardly into each cuff I5 by way of the passage formed between the tubular section =22eand the adjacent propeller bladesurface. In each cuff, the'hot gases flow through theopening 220 of the plate 22a and through the channel defined by the shell I6 and member 22, such hot gases passing outwardly'toward the sealingmember 2!, the hereinbeforedescribed member '22 serving to-defiect a substantial volume of the hot gases toward the leading cuff edge which isparticularly vulnerable when icing -conditions exist. Eventually, all of thehot gases entering'each cuif I5, as described above, pass to the atmosphere byway of a vent I5a formed adjacent-the outer cut! end.

As regards the'cuffs; I5; it will be understood that, to some extent, they: function, by centrifugal action, to draw the 1 hot gases therethrough. However, when cuffs are de-iced in accordance' with theinvention, the source of positive pressure which causes thehot gases'toflow through thepipes: I4" should be such as insures the establishment inthe spinner In of the neces sary gas pressure for causing: flow-'01 gases-outwardly through the cuffs.

Asa result, the blades 5 and'the cuffs I5, for de-icing purposes, are simultaneously subjected to the action' of the hot gases. As regards the spinner II); it maybe de-iced to some extent with the arrangement shown in Fig; 1 by reason" of the fact that-some of the hot gases passing'into the chamber defined thereby flow into-engagement with the front spinner surface. A substantial volume of the. hotgases passes by substantially direct paths'into the blades 5 'andcufis I5 to thereby effectively heat these surfacesfor deicing' purposes; In" the cufls I5, by reason of the presence of the respective members 22,- the heating action ofthe hot gases is highly efi'ective at the respective leading edges thereof.

- It will be understood that the space defined by the spinner I is sealed, entirely or substantially so, from the atmosphere at all times with the exception of the propeller blade vents c, the cuff vents I5a and the inlet ports thereto by way of the pipes 14. The packing seals the joints between the respective sets of tubular sections 22c and tubular members 24. However, during a pitch-changing operation, each tubular section 22c moves rotatably with respect to its associated packing 25 while maintaining a sealing relation.

Referring to my invention as illustrated in Fig. 5, I have shown a hollow propeller blade 5 having an inner circular flange 511 which, in suitable manner, has secured thereto a member 28 serving as a combined diffuser-deflector which may rest upon a blade gear 29 threaded interiorly of said blade 5. a member 30 being utilized for establishing a suitable joint at the blade flange 5d. In accordance with the invention, the deflector 28 comprises an angular section 28a utilizable for deflecting hot gases toward the leading blade edge 5e, this being the blade edge which is particularly susceptible to icing condi tions. In addition, the member 28 has the desirable function of decreasing the velocity of the hot gases passing into the blade 5 by way of the blade passages 5b.

In order to accelerate the rate at which heat is transferred from the hot gases to the material forming the leading blade edge, a plurality of fins 5 or the like may be formed interiorly of the blade 5 throughout all or a part of the area last described. It will be understood that the arrangement of Fig. 5 is particularly advantageous from the de-icing viewpoint, this being true by reason of the fact that the hot gases are efiectively directed toward the leading blade edge while the fins 5f serve advantageously in connection with the transfer of heat to the desired blade area.

Referring to Figs. 1, 2, 2a, 2b and 20, it is a feature of the invention that the aforesaid circular housing I2 defines two communicating chambers I20, I2d which are duplicates of each other. The lower conduit I4, Fig. 2, passes hot gases principally into the chamber I2c at the end thereof having maximum cross-sectional area. Continuing in a clockwise direction, Fig. 2, through the chamber I2c, it will be noted that the cross-sectional area thereof decreases in a progressive manner, Figs. 2a, 2b and 20, said chamber I20 having its smallest cross-sectional area at the end thereof which communicates with the end of the chamber I2d having maximum cross-sectional area. The upper conduit I4, Fig. 2, passes hot gases principally into the chamber IZd at the end thereof having maximum cross-sectional area. Continuing in a clockwise direction, Fig. 2. through the chamber lZd, it will be noted that the cross-sectional area thereof decreases in the same manner as does the chamber I2c, said chamber I2d having its smallest cross-sectional area at the end thereof which communicates with the end of the chamber I20 having maximum cross-sectional area.

The hot gases pass into the rotating spinner ID from the housing I2 through the circular extension I2a and, with a chamber arrangement of the character described above, the tangential component of velocity of the hot gases is maintained at or in a constant ratio to the tangential velocity of the rotating spiner and other parts. This maintains a constant direction of velocity relative to the rotating parts and/or the passage through the circular extension I2a so that there will be a minimum restriction to the flow of the hot gases.

In my copending application Serial No. 503,143, filed September 20, 1943, I have disclosed a heatexchange system utilizable for supplying heated air for de-icing purposes. Such a system is diagrammatically illustrated in Fig. 6 wherein I have shown an aircraft surface W which, for example, may be a surface of a wing. Projecting in the normal direction of aircraft flight is an air scoop 4I having pipes 42 and 43 branching therefrom. The air scoop 4|, then, is at the inlet end 420, of the pipe 42 and it serves as a source of positive pressure to establish a flow of air therethrough, this air, eventually, being discharged from said pipe 42 into the pipes l4, Figs. 1 and 2, which, as previously described, communicate with the housing I2. As shown, the pipe 42 extends through a heating zone 44 and, beyond said zone, said pipe 42 is adapted to communicate with a pipe 45 which branches from the pipe 42 and terminates above the aforesaid surface W in opposite facing direction as regards the air scoop 4|. Disposed at the junction of the pipes 42 and 45 is a valve 46 controlled by a device 41.

The pipe 43, as stated, communicates with the pipe 42 at the air scoop 4 I. The other end of said pipe 43 returns to and communicates with the pipe 42 in a section thereof beyond the zone where the pipe 45 communicates therewith. As shown, the pipe 43 has a valve 48 included therein.

Disposed in the pipe 42, beyond the section thereof with which the pipe 43 communicates, is a suitable temperature-responsive device such, for example, as a thermal bulb 49 which has communicating therewith a. pipe 50 extending in sealed relation through and into the pipe 42.

The pipe 50 communicates with suitable control mechanism 5| such, for example, as described in my aforesaid pending application Serial No. 503,143, filed September 20, 1943. The control mechanism 5| comprises a depending rod 52 which is secured to one end of a suitably mounted pivoted lever 53, the other end of which is secured to the lower end of a link 54' secured, at its upper end, to the actuating handle of the aforesaid valve 48.

The bulb 49, the pipe 50 and a space within the control mechanism 5| are filled with a suitable control medium, either vapor, liquid or a gas. The temperature of the control medium in the bulb 49, as determined by the temperature of the air flowing through the pipe 42, determines the position of the coupled movable system com-, prising the rod 52, lever 53, link 54 and valve 48.

The pipe 42, beyond the aforesaid bulb 49, is shown as having included therein a valve 55, the position of which is rendered dependent upon the quantity (pounds) of air passing, per unit of time, through said pipe 42 beyond said valve 55. Any suitable mechanism may be utilized for controlling the position of the valve 55 and, for purposes of explanation, I have illustrated the quantity control mechanism for the valve 55 as being a duplicate of that used for controlling the valve 48, the same reference characters being applied, respectively, to duplicate parts. As will be noted, the pipe 50a of the quantity control mechanism 5i comprises an angular inlet section 50b extending longitudinally along the pipe 42, the. open end thereof facing the oncoming air stream.

In normal operation, the valve 46 is so posi tioned that the pipe 45 is in non-communicating relationiwith the pipe". During flight of the aircraft, theair scoop 4| continuously supplies air to the inlet end 42a of the pipe 42 and also to the inlet end of the pipe 43. As a result, air passes continuously through the pipe 42 toward the pipes l4 and, while passing through the heatexchange zone 44', the temperature of the air is elevated by heat obtained from the exhaust gases.

The valve 48 is normally partially or entirely closed but in the event that the air passing throughthe pipe 42 becomes warmer than desired, the temperature-responsive control mechanism is actuated by the thermal bulb 49 to produce upward movement of the link 54 where by the valve 48 is opened sufilciently to permit the proper quantity of cool air to flow from pipe 43' to pipe 42 to reduce the temperature of the heated air'passing through said pipe 42.

In the event that the quantity of air traversing the pipe 42 is larger than desired, the air pressure in the pipe 50a increases to thereby actuate. the quantity control mechanism 5| to effect upward movement of the associated link 54 whereby, as a result, the valve 55, which is normally open, is moved toward a closed position.

In the event that the heat-exchange device hereinbefore described becomes unduly heated, the valve 45 may be operated to close off that section of the pipe 42 to the left thereof, Fig. 6, and

to open communication of the pipe 45 with that section of said pipe 42 at the right of the valve 46. As a result, there is an increased flow of cold air through the heat-exchange device by way of the pipes 42 and 45 whereby the temperature of said heat-exchange deviceis lowered.

With respect to Fig. 6, it shall be understood that the invention is not to be limited to the use of either or both of the control mechanisms 5!, the valve 55, the valve 48 together with the pipe 43 and the valve 46 together with the pipe 45.

Hence, Fig. 6 is illustrative of the broad idea of passing a stream of heated air or other hot gases into engagement or heat-exchange relation with an aircraft surface to be de-iced in response to the application to said stream of two pressure eifects, namely, (1) positive pressure, whether generated by an air scoop, a pump, or equivalent and (2) negative pressure, i. e., the centrifugal action of the propeller'blades and also of the propeller blade cuffs, if used and if desirable. In other words, in the disclosed form of the invention, a path for de-icing air extends from the inlet end 42a of the pipe 42, thence by way of the pipe 42, pipes l4, housing I2, the chamber de- Referring to Fig. 8, I have shown-the herein before described flanges la and So as having spaced connecting webs associated therewith and secured thereto. Received and supported in a pair of the webs 60, diametrically opposite each other, are the ends of the respective pipes 6| which extend forwardly-through the spinner I0. The'pipes 64 Join each other in a neck 62 which extends through a shell 63 conforming generally with the interior front surface of said spinner ll, said shell 63 being spaced from the spinner I 0 and secured thereto in suitable manner.

It will be understood that the pipes 14 forming a part of the arrangement of Figs. '7 and 8 are traversed by heated air or hot gases which is supplied thereto in suitable manner, for example, as illustrated in Fig. 6. If so, it will be understood that the heated air and hot gases pass through the propeller blades 5 of Figs. '7 and 8 in response to the application thereto of two effects, namely, the pressure generated at the air scoop and the centrifugal action of the propeller blades. Simultaneously, the same two effects cause heated air or hot gases to pass from the housing. I! through the pipe 6| and thence into the space between the shell 63 and the interior front sur face of the spinner H), such heated air or hot gases passing into the spinner chamber proper from the ends of the shell 63 and thereafter passing to the atmosphere either by way of the pro-' peller blades 5 or the cuffs Hi. In this manner, the heated air or hot gases is or are effectively applied to the spinner nose for de-icing purposes.

Although in a preferred form of my invention; the hot gaseous medium which is passed into the spinner I9 is heated air which is obtained in the manner described in my aforesaid pending application Serial No. 503,143, filed September 20, 1943, it shall be understood that my invention is not to be thus limited. Thus, for example, the heated air'may be obtained in any other suitable manner and, moreover, the invention is not to be limited to the use of heated air since other heated mediums such, for example, as the hot exhaust gases of the aircraft engine may be used for de-icing' purposes in accordance with a broad application of my invention.

In the appended claims, the expression deicing shall be understood as describing true deicing wherein that ice is melted which, previously, had been formed on the described rotating aircraft surfaces, i. e., the propeller blades 5, the spinner m or the cuffs I5 and said expression shall also be understood as describing an operation wherein said aircraft surfaces are subjected to the action. of a hot gaseous medium in order to' positively prevent the formation of ice thereon.

Although I have shown de-icing systems for a rotatable system comprising a spinner, propeller blades and associated cuffs, it shall be understood, except as limited by the appended claims, that my invention is not to be limited to the use of cuffs with the respective propeller blades.

While the invention has been described with respect to certain particular preferred examples which give satisfactory results, it will be understood by those skilled in the art after understanding the invention, that various changes and modifications may be made without departing from the spirit and scope of the invention and it is intended therefore in the appended claims to cover all such changes and modifications.

What is claimed as new and desired to be'secured by Letters Patent is:

' 1. In combination, a hollow propeller blade and an associated cufi, said blade having an inlet opening in the shank thereof and a vent at or adjacent the tip thereof, said cuff having an inlet opening at the inner end thereof and a vent adjacent its tip, means for supporting said blade and cuff for rotatable movement, means for supplying streams of hot gases which pass through the respective inlet openings of said blade and cufl. for subsequent discharge to the atmosphere by way of the respective vents, and means for directing the respective streams of hot gases toward the blade and cuff leading edges.

2. In a de-icing system for a propeller having a blade and a hollow cuff on the blade shank, the leading edge of said cuff being subject to ice accretion in operation, a bafile within the cuff defining with the inner surface thereof a thin passage whose surface is substantially co-extensive in length with the cuff and substantially coextensive in width with the leading edge portion of the cuff which is subject to ice accretion and whose depth is substantially uniform and less than said width, means to feed hot gas to one end of said cuff passage for substantially laminar flow through the passage and over the surfaces of said cuff and baflie and means to provide egress of said hot gas from the other end of said cuff passage.

3. In a de-icing system for a propeller having a hollow spinner and hollow blades, means to introduce hot gas Within the spinner, means to confine the hot gas entering the spinner to the inner surface thereof at that part of the spinner which is subject to ice accretion, and a nozzle in each blade shank for conducting hot gas from said spinner hollow to the blade hollows, said nozzles being disposed to direct hot gas entering the blade hollows along the interior of the blade leading edges, said blades having ports for exit of hot gas.

4. In a de-icing system for a propeller having a hollow spinner and hollow blades, means to introduce hot gas within the spinner, means to confine the hot gas entering the spinner to the inner surface thereof at that part of the spinner 10 which is subject to ice accretion, and a nozzle in each blade shank for conducting hot gas from said spinner hollow to the blade hollows, said nozzles being disposed to direct hot gas entering the blade hollows along the interior of the blade leading edges, said blades having ports for exit of hot gas, the inner surface of said blade leading edge having a plurality of projections thereon in contact with the hot gas stream to augment heat transfer between the blade materials and the hot gas.

EVERETT P. PALMATIER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,864,438 Janson June 21, 1932 1,879,717 Sikorsky Sept. 27, 1932 1,899,689 Houston Feb. 28, 1933 1,942,674 Whittsett Jan. 9, 1934 2,046,521 Mahaifey July 7, 1936 2,244,800 Pascale June 10, 1941 2,256,393 Klein Sept. 16, 1941 2,389,400 Woods July 12, 1942 2,318,233 Keller May 4, 1943 2,320,870 Johnson June 1, 1943 2,394,513 Chappdelaine Feb. 5, 1946 2,469,480 Sikorsky May 10, 1949 FOREIGN PATENTS Number Country Date 97,141 Sweden Oct. 7, 1934 525,452 Great Britain Aug. 28, 1940 837,466 France Nov. 1-2, 1938 

